The present invention relates generally to communication of information, and more particularly, to a method and system for compressing information for a current device based on either previous information of the current device or previous information of another device that is coupled to the current device through a shared communication medium.
One system design consideration is the reduction of bandwidth needed to communicate information across a network. Since the bandwidth of the communication medium is limited, it is desirable for the system to reduce the bandwidth needed to communicate information as much as possible. A particularly challenging application is the transmission of video over wireless networks. Even when video is compressed, there is a valid concern of the use of excessive bandwidth, especially to transmit the same, similar, or related content by many devices in a network. Consider the problem of N devices in the network attempting to communicate exactly the same information. Current approaches require N times the amount of bandwidth needed for one device to communicate the information. As can be appreciated, it would be desirable to decrease the amount of bandwidth needed for such a situation.
As an example, consider the case of three people with three video cameras capturing a scene. All three cameras are seeing different portions of the same scene. Therefore, compressing the video while accounting for the information available to all the cameras can require significantly fewer resources than the conventional approach where each camera performs an independent compression using only its own information.
A second system design consideration is the reduction of the power needed by the transmitting device to communicate information. Since the devices are typically a portable device that requires the use of a portable power supply, such as batteries, any design should consider how to increase the life of the batteries by reducing the amount of power that is needed to transmit information.
Based on the foregoing, there remains a need for a method and system for a mechanism to provide efficient communication between a sender and a receiver across a shared communication medium that overcomes the disadvantages set forth previously.
In accordance with the invention, a compression and transmission method and system for use to communicate information from a first device to a second device in a network of devices are described. First, the first device receives information to be communicated to the second device. Second, the first device compresses the information to be communicated by employing prior information of the first device and prior information of the second device. The compressed information is then transmitted to the second device.
In one embodiment in accordance with the invention, the devices are connected via a shared communication medium, and a single device transmits at any one time. When the transmitting device is transmitting, all the other devices (i.e., non-transmitting devices) are in receive mode. During receive mode the non-transmitting devices listen to, record, and may also decode the information received from the transmitting device, which is coupled to the non-transmitting devices through the shared communication medium. A current device awaits a transmission slot. During transmit mode, the current device receives information to be transmitted (e.g., a live video feed or audio feed), encodes the information based on either previous information from the current device, previous information from another device, or the previous information from the current device and one or more other devices, and transmits the encoded information through the shared communication medium. During transmission, all the non-transmitting devices are in receive mode.
In another embodiment in accordance with the invention, a compression and transmission system is described. A plurality of devices is coupled together through a network (e.g., the Internet). Each device includes a decoder and an encoder. During a receive mode, the current device employs the decoder to decode all the information that is transmitted by the other devices that are coupled to the current device through the shared communication medium. During a transmit mode, the current device employs the encoder to encode the information to be transmitted based on either previous information transmitted by the current device or previous information transmitted by the other devices in the network.
Other features and advantages of the present invention will be apparent from the detailed description that follows.